Manufacture of dinitriles from thiodinitriles

ABSTRACT

The invention is the extrusion of sulfur from thiodinitriles to obtain the corresponding dinitrile by heating the thiodinitrile at a temperature of 200* to 700*C. For example, sulfur is extruded from thiodipropionitrile to obtain adiponitrile. This extrusion reaction can be either a strictly thermal reaction employing no other reactant or a reaction conducted in the presence of other gases, liquids or solids.

United States Patent Callahan MANUFACTURE OF DINITRILES FROMTHIODINITRILES Inventory James L. Callahan, Wooster, Ohio Assignee: TheStandard Oil Company,

, Cleveland, Ohio Filed: Nov. 18, 1974 Appl. No.: 524,729

US. CL... 260/465.8 R; 260/465 l-l; 260/465.l; 260/465.9 Int. Cl. C07C120/00; C07C 121/20;

C07C 121/26; C07C 121/64 I Field of Search 260/465.8 R, 465 H ReferencesCited UNITED STATES PATENTS 5/1965 LaCombe et a1. 260/465.9 X

3,424,784 1/1969 Barsly 260/465 8 R Primary Examiner-Joseph P. BrustAttorney, Agent, or FirmHerbert D. Knudsen [57] ABSTRACT The inventionis the extrusion of sulfur from thiodinitriles to obtain thecorresponding dinitrile by heating the thiodinitrile at a temperature of200 to 700C. For example, sulfur is extruded from thiodipropionitrile toobtain adiponitrile. This extrusion reaction can be either a strictlythermal reaction employing no other reactant or a reaction conducted inthe presence of other gases, liquids or solids.

15 Claims, No Drawings MANUFACTURE OF DINITRILES FROM THIODINITRILESBACKGROUND OF THE INVENTION SUMMARY OF THE INVENTION The presentinvention is a process for producing a dinitrile of the formula NCRR'CNfrom a thiodinitrile of the formula NC-R"SR"CN wherein R, R, R" and R'are aliphatic or aromatic hydrocarbon radicals; and

wherein R and R have the same number of carbon atoms and R and R havethe same number of carbon atoms comprising heating the thiodinitrile ata temperature of 200 to 700C. Employing the present invention gives highyields of the desired dinitrile. Of special interest in the invention isthe production of adiponitrile from thiodipropionitrile.Thiodipropionitrile shall hereinafter be referred to as TDPN.

The central feature of the present invention is the fact that sulfur canbe thermally extruded from thiodinitriles of the formula shown above.Extrusion of the sulfur from these compounds leaves the correspondingdinitrile.

The most important feature of the invention is the reaction temperature.Broadly as noted above, the reaction temperature may range from about200 to about 700C. Within the broad temperature range, temperaturesbetween 300 and 650C. have been shown to give the most desirableresults, with temperatures in the range of 400 to 600C. being especiallyuseful to give reactions that have especially high commercial potential.

Within the temperature ranges claimed, the reaction of the presentinvention can be conducted in the vapor or liquid phase. Of specialinterest in the present invention are reactions conducted in the vaporphase. These reactions have been shown to be especially desirable forthe production of the dinitrile. Of course, to obtain a liquid phasereaction within the higher temperature ranges of the invention, pressuremust be applied. It is anticipated that a reactor pressurized withhydrogen and/or acrylonitrile would give the most desirable results.

Although the thermal extrusion of the thiodinitrile is the centralfeature of the invention, of greater desirability because of the highyields involved is the conduct of the extrusion in the presence of asolid. Of special interest is the use of a solid that is a metal ormetal containing material.

Among the metals that may be employed in the reaction', those selectedfrom the group consisting of elements of Group IIIA, IVA, VA, VIA, IB,IIB, VB, VIB, VIlB or VIII are preferred. Of these numberous metals,

it has been found that iron, nickel, manganese, copper, silver and tinare of greatest interest with theuse of iron or copper being of greatestsignificance because of the especially desirable yields obtained usingthese solids.

2 These metals may be used alone or in alloys or mixtures.

The reaction conditions other than the temperature limitation are notcritical. However, there are certain preferred aspects of the reactionto give most desirable results.

In the-vapor phase reactions, it has been found that the use of anadditional gas in the reactant feed is desirable to purge the productsthrough the reactor. When a heterogeneous solid is employed, this purgegas is also believed to draw the products off the surface of the solidand into the effluent from which the dinitrile is recovered. Essentiallyany gas maybe employed in the reaction. Representative examples of thesepurge gases include nitrogen, air, acrylonitrile, carbon monoxide,carbon dioxide, argon, hydrogen and the like. Of special interest as faras the purge gases are concerned is the use of hydrogen, acrylonitrileor mixture thereof. These gases appear to not only act as a purge gasbut also act as promoters of the reaction of thiodipropionitrile to givedesirably high yields.

The pressure employed in the reaction may vary widely. Subatmospheric,superatmospheric or atmospheric pressure may be employed. The contacttime may range from less than a second to a number of hours depending onthe reaction temperature and state of reaction.

The reactor employed in the invention can be an open tube with an inletfor reactants and an outlet for products. In the preferred practice ofthe invention, this open tube could be at least partially filled with asolid as described in the Specific Embodiments. The reactor could takethe form of either a fixed-bed reactor with a solid fixed in thereaction zone or a fluid-bed reactor. Although a fixed-bed reactor hasbeen employed in all of the experiments of the Specific Embodiments, itis anticipated that a fluid-bed reactor could be employed to greatadvantage in the present invention.

When a heterogeneous solid is employed, there is a tendency for theheterogeneous solid to become sulfided during the course of thereaction. This sulfiding is especially noticeable when a metal isemployed. As the catalyst becomes sulfided, it tends to lose activityfor the desired reaction. Even though some catalysts are enhanced bypartial sulfiding, there is a point of sulfiding at which regenerationappears to be desirable. Normally, the regeneration involves at leastpartial return of the sulfided metal to the metallic state or a lowervalence state. This can be suitably accomplished by the action ofhydrogen or another reducing agent on the catalyst or in a moreconvenient method, the catalyst may be oxidized with air and thenreduced with a reducing agent. Using either technique, the catalyticactivity of the heterogeneous solid has been observed to be restored.

The recovery and purification of the dinitrile product is normally veryconvenient. The reactor effluent contains unreacted thiodinitrile, thedinitrile product and mononitriles of the formula HRCN formed bybreaking the sulfur out of the thiodinitrile without joining the carbonatoms and these combustion gases. The thiodinitrile, dinitrile andmononitrile are then sequentially and selectively condensed from thereactor effluent according to the disparity in their boiling points. Thethiodinitrile is conveniently recycled to the reactor, the dinitrile ispurified and the mononitrile can be reacted with H S to form thethiodinitrile starting material. The purification of the dinitrileusually consists mainly of hydrogenating ethylinic unsaturation found inthe final product if the saturated product is desired.

Special mention of the reaction of TDPN to form adiponitrile iswarranted in view of the extreme commercial importance of this reaction.Adiponitrile, as is well known, is an important intermediate in theproduction of nylon. It appears that the present invention provides adramatic improvement in the method of making adiponitrile. The TDPNemployed as the starting material can be easily prepared from hydrogensulfide and acrylonitrile. Furthermore, in the reaction of TDPN, one ofthe major by-products is acrylonitrile that could be convenientlyrecycled for reaction with hydrogen sulfide to produce more of the TDPN.As noted above, this reaction is the central focus of the presentinvention, even though other dinitriles can be conveniently prepared bythe process of the invention.

SPECIFIC EMBODIMENTS EXAMPLE 1 Thermal Extrusion of Sulfur fromThiodipropionitrile A reactor was constructed of a 8.0 mm. insidediameter stainless steel tube. The reactor has a cc. reaction zone, aninlet for reactants and an outlet for products. The reactor was heatedin a salt bath to give the desired reaction temperature.

The thermal extrusion of sulfur from TDPN was conducted at a temperatureof 505C. using a reactant feed of 0.06 cc. per minute of TDPN measuredas a liquid and a nitrogen purge of 8 cc. per minute measured as a gasat a standard temperature and pressure. The products were collected inchloroform and analyzed by gas liquid chromotography. The nature of theproducts was confirmed by mass spectrostophy. For purposes of reportingthe yield, adiponitrile includes amounts of unsaturated dinitrilesproduced such as 1,4-dicyanobutene-2. The amounts of these by-productswere less than in all experiments. The remaining by-products werepropionitrile and acrylonitrile. In this exper iment, 16.4% of the TDPNfed was converted to products and of the TDPN converted, 7.0% wasadiponitrile. For purposes of this application, the followingdefinitions are used:

moles of a TDPN reacted X 100 convfirsion moles of TDPN fed moles ofadiponitrile formed X 100 moles of TDPN reacted In the reactor describedabove, various solids other than iron and copper were used to convertTDPN to 4 adiponitrile. The solids for these reactions were prepared asfollows:

EXAMPLE 2 Aluminum The reaction zone was charged with 10 cc. of /s X A;inch aluminum tablets that were obtained from compression of aluminummetal powder in a compression mold.

EXAMPLE 3 Active carbon The reaction zone was filled with 10 cc. of10-20 mesh Witco active carbon sold as Grade 1 l8.

EXAMPLE 4 Silica gel The reactor was filled with 10 cc. of 10-20 meshsilica prepared by drying Nalco 1040A silica sol at 125C. and calciningthe resulting product in air for 1 hour at 350C.

EXAMPLE 5 Molybdenum The reactor was filled with 10 cc. of solidprepared as follows: 54 g. of molybdenum metal powder was mixed with 20g. of 34% silica sol to form a uniform mixture. The resulting mixturewas dried and reduced in a flow of hydrogen for one hour at 540C.

EXAMPLE 6 EXAMPLE 7 Vanadium The reaction zone was filled with 6 cc. ofcoarse vanadium turnings measuring approximately /s X 1/16 inch.

EXAMPLE 8 Silicon carbide The reaction zone was filled withapproximately 7 cc. of 9-40 mesh crushed silicon carbide pellets soldunder the tradename Norton BC-132.

EXAMPLE 9 Nickel The reactor was filled with 10 cc. of 10-20 mesh nickelcatalyst prepared by mixing 173 g. of nickel powder and 35 g. of 34%silica sol. The solid was pretreated with TDPN for 18 minutes at 450C.,prior to the reaction.

The catalyst above were used to convert TDPN to adiponitrile under theconditions and using the feeds shown in Table 1.

Table 1 Use of Solids Other than Iron and Copper in the Production ofAdiponitrile Feed, cc/min. Results,

Gas/ Example Solid TempC. TDPN AN* Flow Conversion Yield 2 Aluminum 5400.45 N /2 63.5 3.2 3 Active Carbon 480 0.06 N-,/8 10 4 Silica Gel 5050.06 N /8 100 10 5 Molybdenum 540 0.01 0.05 N /8 95.5 4.4 6 Cobalt 5400.01 0.06 N- IS 100 1.0 7 Vanadium 540 0.02 0.009 N /S 58.9 5.9 8Silicon Carbide 535 0.02 H /5 46.9 13.7

Table l-continued Use of Solids Other than Iron and Copper in theProduction of Adiponitrile Feed, cc/min. Results, j Gas/ Example SolidTempC. TDPN AN* Flow Conversion Yield 9 Nickel 0.038 N /6 100 8.1

AN Aerylonitrile EXAMPLES -28 Use of Various Forms of Copper Copper invarious forms was tested in the reactor shown above. Each examplerepresents a run of 8.5 minutes using a 0.024 cc.- per minute flow ofTDPN and 0.094 cc. per minute flow of acrylonitrile, both measured as aliquid, and a gaseous flow of hydrogen at a rate of 5 cc. per minuteunless otherwise noted. The various catalysts employed and any treatmentof the catalyst during the reaction is discussed below.

EXAMPLES 10-13 Cu on SiC Silicon carbide was placed in a solution ofcopper chloride. To this mixture, hydrazine was added to reduce thecopper and deposit the copper on the silicon carbide. The reactor wascharged with 5 cc. of the catalyst, and the catalyst was reduced in astream of hydrogen for 1 hour at 540C. After Example 10, the reactor waspurged with hydrogen for 30 minutes. After Example 11, air was passedthrough the reactor for 30 minutes at 540C. followed by a hydrogenreduction at 540C.for 25 minutes. After Example 12, there was an airregeneration and a hydrogen reduction, each of which lasted for minutesat 540C.

EXAMPLES 14-15 Etched Cu wool Etched Cu wool was prepared by etchingcoarse Cu wool with a solution of nitric acid; 6 cc. of the catalyst wascharged to the reactor. After Experiment 14, the reactor was flushedwith hydrogen at reaction temperature for four hours.

EXAMPLES 16-18 Fine Cu wool .The reactor was charged with 2 cc. of extrafine Cu wool prepared by etching coarse Cu wool with nitric acid andreducing the Cu wool for 1 hour at 540C. with hydrogen. There was notreatment of the copper after Examples 16 or 17.

EXAMPLES 19-22 Bonded Cu flake The reactor was charged with 1 cc. offine copper wool and 6 cc. of bonded Cu metal flake pigment made bymixing fine copper powder with glycerol to form a thick paste, dryingthis metal overnight at 125C, calcining it at 500C. for 15 minutes inair, grinding the dried mixture to 9-40 mesh and reducing the flake at545C. for one hour with hydrogen. After Example 19, the reactor waspurged with hydrogen for 40 minutes. After Experiment 20, the reactorwas purged with hydrogen for 40 minutes. After Experiment 20, thereactor was purged with hydrogen for 1.5 hours. After Experiment 21, thereactor was purged with hydrogen for 0.75 hours. 7

EXAMPLES 23-28 Reduced CuO wire The reactor was charged with 5 cc. ofMallinkrodt wire form copper oxide which had been reduced overnight in ahydrogen stream at 540C. After Example 23, the reactor was purged withhydrogen for 20 minutes. After Examples 24 and 25, the reactor waspurged with hydrogen for 30 minutes. After Example 26, the catalyst wasregenerated in air at 540C. and reduced with hydrogen for one hour.After Example 27, the reactor was purged with hydrogen for 20 minutes.

The results obtained using these forms of copper are summarized in Table2.

Table 2 Use of Different Forms of Copper for the Production ofAdiponitrile from TDPN Results,

Example Solid TempC. Conversion Yield 10 Cu on SiC 540 84.8 53.0 l l 55069.6 63.3 12 540 87.9 52.0 13 42.2 14 Etched Cu W001 535 62.1 55.1 15545 60.7 80.0 16 Fine Cu wool 550 69.6 60.8 17 65.2 79.6 18 570 72.869.6 19 Bonded Cu flake 545 92.4 60.0 20 540 66.5 71.3 21 60.7 82.9 22555 62.1 91.6 23 Reduced CuO wire 540 87.9 42.8 24 72.8 69.0 25 69.672.5 26 560 75.9 58.0 27 550 72.8 51.6 28 68.3

EXAMPLES 29-40 Cu Catalysts and Modified Cu Catalysts EXAMPLE 29 Cu shotThe reactor was filled with Cu shot measuring 2-3 mm. in diameter.

EXAMPLE 30 Silver plated Cu shot Approximately 10 cc. of Cu shot wastreated with a dilute solution of silver nitrate to deposit a ,smallamount of silver metal on the shot.

EXAMPLE 31 Silver Cu'alloy The reactor was charged with 7 cc. of acopper-silver alloy shot having a 4; inch diameter. This copper-silvershot is commonly known as coil silver. I

catalyst which had been reduced in hydrogen for four EXAMPLE 32 hours at540C. Subsequent to each of the runs, there Tin coated Cu shot Thereactor was charged with was a flow of hydrogen over the catalyst for 20minutes 10 cc. of approximately 1/32 inch diameter tin coated atreaction temperature. Subsequent to Example 44.

copper particles. The tin coated copper particles were there was anoxidation in air overnight and reduction supplied by LaboratoryEquipment Company as part with hydrogen for a period of 1 hour.Subsequent to 501-263. Example 48, the catalyst was oxidized in air forone hour and then reduced with hydrogen for 1 hour. The EXAMPLES 33 36results of these experiments are shown in Table 4. The Cu turnings Thereactor was charged with cc. 10 reaction temperature in each case was540C. except of light Cu turnings that were well packed into the wherenoted. reaction zone. ln- Example 34, fresh copper turnings Table 4 wereagain charged to the reactor. In Example 35, fine Cu turnings werecharged to the reactor and reduced Continuous Run Using Catalyst ofCopper on Silicon Carbide with hydrogen for one hour at 540C. In Example36, Results, A the catalyst was used in the condition found after Ex-Example C(mversio Y'eld ample 35." 41 I00 42.2 1 I 42 86.2 5 EXAMPLE 3743 60.7 61.9 44 42.4 ZlIlC plated Cu turnings The reactor was charged45* 86.2 416 with 7 cc. of fine Cu turnings which were electroplated 2?2 22:; with a very thin layer of zinc from a zinc sulfate solug 1 86:25- tion using a zinc anode and dry cell batteries for cur- 49 *535C.rent. a

EXAMPLE 38 Manganese plated Cu turnings The reactor was EXAMPLES 50-61Use of Cu Metal on Silicon charged with 7 cc. of fine Cu turnings whichwere elec- Dioxide troplated with a solution containing manganese chloslon dioxnde and ammomum ch10 de. Various catalysts of Cu metal powder on1 1C ide were prepared. These catalysts were used in the EXAMPLE 39conversion of TDPN to adiponitrile under the conditions noted in Table5. The catalysts for these reactions Cu turnings Hg addition The reactorwas d f Hows, charged with 7 cc. fine copper turnings and 0.35 cc. ofwere prepare as o Hg added to the feed in approximately 20 equal incre-EXAMPLES -54 ments during the l7-minute run. The catalyst was preparedby mixing Cu powder with EXAMPLE 40 a 34% silica sol to form a uniformmixture. The mixture was dried at 540C. in air for one hour and reducedCu tummgs chloroform addmon The reactor with hydrogen for 2 hours at510C. Examples 51 and was charged with 7 cc. of fine copper turnings andto 40 52 employed fresh catalyst prepared as described gi s ix 221231:2:; zgg 'g per mmute of above. Example 53 was run using the catalyst ofExam- The results of these experiments are shown in Table ple 52 afterreduction at 540 for l hour wlth hydrogen. Example 54 employed acatalyst prepared above 3' sintered at 1 hour at I000C. and reduced inhydrogen Table 3 Copper Catalysts and Variations of the Copper CatalystsLength of Feed cc/min.

Example Solid Run. Min. Temp C. TDPN AN N Conversion Yield 29 Coppershot 30 530 0.02 4 5] [6.6 30 Silver plated copper shot 18 505 0.056 878.2 4.6

' 3| Silver copper alloy 8.5 540 0.024 0.094 5 39.3 46.3 32 Tin coatedcopper I8 495 0.056 7 67.3 6.2 33 Cu turnings 29 525 0.0l 5 0.061 5 69.428.3 34 13 543 0.062 '4 72.8 59.5 35 26 546 3 88.4 51.5 36 26 550 5 82.654.0 37 .Zn plated Cu turnings I7 535 0.024 0.094 I00 33.) 38 Mn platedCu turnings I6 540 0.025 0.l00 89.3 27.9 39 Cu turnings, Hg addition 17535 0.024 0.094 52 60.5 40 Cu turnings, CHCl addition 17 540 0.0l 50.060 6 38.6 34.6

' at 540C. This catalyst was then pretreated by feeding EXAMPLES 41-49commuous run usmg Cu on 0.2 cc. TDPN and 0.8 cc. of acrylonitrile in ahydrogen slhco carbide stream at 540C. over the catalyst in 5 minutes. Anumber of 8.5 minute runs using a feed of 0.024

cc. per minute of TDPN and 0.094 cc. per minute of EXAMPLE 55acrylonitrile measured as a liquid and 5 cc. per minute The reactor wasfilled with a first layer of 2 cc. of H8 of hydrogen were run using acatalyst of Cu on silicon inch Cu shot, a second layer of 3 cc. of thecatalyst carbide. The reactor was charged with 7 cc. of the prepared inExample 50 above and a third layer of5 cc.

Cu shot. This catalyst mixture was reduced in hydrogen for 1 hour at540C.

EXAMPLES 56-57 The reactor was charged with 10 cc. of 1020 mesh Icatalyst prepared by grinding 207 g. of Cu oxide to a fine powder andcombining this powder with 41 g. of Nalco silica sol. The mixture wasmixed into a paste and dried at 120C. overnight. The dried solid wasthen heated in air for 2 hours at 1000C. and then ground and screened toa 2030 mesh fraction. The resulting solid was calculated to contain92.2% copper metal with the remainder being silicon dioxide. Thiscatalyst was reduced for 1.5 hours at 525C. During the course of thereaction, dimethyl sulfide was added to the feed. The catalyst fromExperiment 56 was reduced with hydrogen at 530C. for 30 minutes and usedin Example 57.

EXAMPLES 58-61 The catalyst prepared for Example 56 was promoted withvarious elements to form the catalyst employed in these examples. Forthe catalyst containing platinum, 5 cc. of the Cu catalyst prepared inExample 56 was impregnated with 1.9 g. of a solution of platinumchloride. To prepare the catalyst containing potassium, 5 cc. of thecatalyst of Example 56 was impregnated with 0.095 g. of potassiumhydroxide dissolved in a small volume of water. To prepare the catalystcontaining phosphorus, 5 cc. of the catalyst used in Example 56 wasimpregnated with 0.16 g. of 85% phosphoric acid. To prepare the catalystcontaining bismuth, 5 cc. of the catalyst employed in Example 56 wasimpregnated with 1.54 g. of Bi(No .5H O dissolved in nitric acid.'lneach preparation the resulting material was dried and heat treated at500C. for 1 hour.

The results of the experiments using these catalysts and conditions isshown in Table 5.

Table 5 I EXAMPLES 62-76 Use of iron catalysts.

Various iron catalysts were prepared and tested. The

catalyst preparations and reactions are described below. The results ofthese experiments are shown in Table 6.

EXAMPLES 6266 A catalyst of 93% iron powder and 7% silica were preparedby mixing iron powder and silica sol, drying the mixture, calcining thedried product and reducing the calcined product with hydrogen. InExamples 62, 63 and 64, fresh catalyst was employed. In Example 65, thecatalyst was sintered in air at 1000C. and reduced in hydrogen at 525C.for one hour. Example 66 used the catalyst in the same manner as Example65 except that the reduction took place at 540C.

EXAMPLES 67-70 The reactor was charged with 1 cc. of fine steel wool atthe bottom and 6 cc. of bonded iron metal made by mixing fineelectrolytic iron powder with glycerol to form a thick paste, drying theresulting paste at 180C. for 2 hours, heating the dried material in acovered container at 500C. for 30 minutes and grinding and screening thesolid to a 9-40 mesh material. This catalyst was reduced with a hydrogenstream in the reactor for 2 hours at 540C. After the experiment ofExample 67, the reactor was purged with hydrogen for 1 hour at 68. Thereaction was continued in Examples 69 and 70.

EXAMPLES 71-76 The reactor was charged with 10 cc. of iron chipsmeasuring approximately A: inch in diameter. 1n Examples 72 and 73, thereaction with the charge of Example 71 was continued. In Example 74, thecatalyst used in Example 73 was employed and hydrogen was used as CopperMetal Powder on Silicon Dioxide and Variations Thereof in thePreparation of Adiponitrile Run Time Feed, cc/min. Results, ExampleSolid Temp C. Min. TDPN AN Gas/Flow Conversion Yield 90% Cu powder 40517 0.059 N /8 100 8.7

10% SiO 51 510 61 0.013 0.052 N /7 100 22.4 52 455 65 97.7 10.8 53 5450.015 0.058 H /5 100 30.1 54 540 8.5 0.024 0.094 H /20 100 17.8 55 Cushot/CuSiO: 545 18 0.056 N /5 95.8 17.9 56 CuSiO +0.15 520 18 0.222 10013.1

dimethyl sulfide 57 CuSiO 540 43 0.019 0.074 100 34.0 58 CuSiO, Ft 525 90.011 0.044 N /4 100 29.1 59 CuSiO K 540 13 0.015 0.062 N /7 100 19.1 60CuSiO P 525 13 N- IS 83.5 36.8 61 CuSiO Bi 525 13 100 22.7

Table 6 Use of Various lron Catalysts in the Production of AdiponitrileRun Time Feed. cc/min. Results, Example Catalyst Min. TempC. TDPN ANGas/Flow Conversion Yield 62 93% Fe powder 7% Si0 34 505 0.029 N /3.54.9 63 17 540 0.059 N /14 100 5.9 64 18 400 0.056 N /8 100 4.3 65 18 5200.056 N /8 6.6 66 33 540 0.024 0.094 H /20 13.0 67 Powdered Fe 8.5 5400.024 0.094 H /5 17.9 68 H I, H H H H 277 540C. and the resultingcatalyst was used in Example Table 6-continued Use of Various lronCatalysts in the Production of Adiponitrile Run Time Feed. cc/min.Results,

Example Catalyst Min. TempC. TDPN AN Gas/Flow Conversion Yield 69 H HH26 H 341 70 H H 525 n H y, 38]

71 Fe chips 1/8 17 510 0.058 N /3.5 8.5

EXAMPLES 77-93 Use of Various Steel Wool EXAMPLE 83 Catalysts.

Various steel wool catalysts were prepared and tested under theconditions described below. The results of these tests are summarized inTable 7.

EXAMPLES 7778 Fine steel wool was reduced in a stream of hydrogen forminutes at a temperature of 530C. The catalyst of Example 78 employedthe catalyst of Example 77 that had been purged with nitrogen after therunning of Example 77.

EXAMPLES 79-80 The reactor was charged with 7 cc. of very fine steelwooland reduced in hydrogen for 30 minutes at 540C. After Example 79,the reactor was purged with hydrogen.

EXAMPLE 81 The reactor was charged with 8 cc. of steel wool, and duringthe course of the reaction, 0.001 cc. per minute of chloroform, measuredas a liquid, was added.

EXAMPLES 8487 The reactor was charged with 7 cc. of fine steel wool anddifferent purge gases were employed.

EXAMPLES 88-89 Fresh steel wool was employed.

EXAMPLES 90-91 Approximately 10 cc. of course steel wool was charged tothe reactor in Example 90. In Example 91, 7 cc. of fine steel which hadbeen etched with a dilute solution of sulfuric acid was employed.

EXAMPLE 92 The reactor was charged with 7 cc. of fine steel wool whichwas electroplated with a very thin layer of zinc from a zinc sulfatesolution and a zinc anode, and dry cell batteries were used forelectrical current.

EXAMPLE 93 The reactor was charged with 7 cc. of fine steel wool and0.35 cc. of Hg was added in 20 equal increments during the course of thereaction. In the same manner as shown above, TDPN was passed over thesecatalysts EXAMPLE 82 under the conditions shown in Table 7.

Table 7 Use of Steel Wool Catalysts And Variations Thereof Feed, cc/min.Results, Example Solid TempC. TDPN AN Gas/Flow Conversion Yield 77 Steelwnol 525 0.015 0.062 N /6 100 39.1 78 Steel wool 541) 0.057 0.023 N /793.3 54.3 79 Steel W001 540 0.016 0.640 94.2 58.5 80 Steel W001 5400.200 0.400 H /7 88.4 53.4 81 Cu treated steel W001 535 0.160 0.640 N /S70.1 54.8 82 Cu plated steel W001 540 0.025 0.100 N /7 85.0 45.9 83Steel wool. chloroform 535 0.011 0.038 N /7 89.0 50.1

addition 84 Steel wool 535 0.015 0.062 CO/7 95.1 44.8 85 Steel W001 5350.133 0.533 CO/lO 84.2 46.4 86 Steel W001 535 0.057 0.023 air/7 91.742.6 87 Steel wool 540 0.050 0.200 air/9 94.2 12.3 88 Steel wool 5700.145 0.582 N /6 87.5 520 89 Steel wool 570 0.020 0.080 N- /S 95.8 43.590 Coarse steel W001 540 0.015 0.062 87.5 49.7 91 Acid etched fine steelW001 540 0.057 0.229 N /5 92.6 55.6 92 Zn plated steel W001 535 0.0240.094 10.7 93 Steel wool, Hg addition 98.4 46.2

Cu was electroplated on steel wool from copper sulfate solution using a1.5 volt battery.

EXAMPLES 94-97 The Affect of Additives.

Various compounds were added to the feed gas using a catalyst of ironparticles described above. The results using these additives are shownin Table 8.

Table 8 Effect of Various Additives to the Extrusion Reaction Using aCatalyst of iron Particles assumed EXAMPLES 98-105 Production ofadiponitrile from TDPN using a 50-50 mixture of copper and iron powder.

Table 9 Production of Adiponitrile from TDPN Using a 50-50 Mixture ofCopper and Iron Powder Results.

Example TempC. Conversion Yield 99 30.6 100 35.8 lOl 35.8 lOZ 34.1 103480 86.2 35.6 l04 565 87.9 33.6 lO 81.7 47.5

In the same manner as described above for the reaction ofthiodipropionitrile, other thiodinitriles can be reacted. For example,NCCH SCH CN can be reacted to form NCCH CH CN, NCCH CH CH CH SCH CH CHCN can be reacted to NCCH CH --CH CH CH CH CH- CN and NCCH SCH CH CN canbe reacted to form NCCH CH CH CN.

I claim:

1. A process for producing a dinitrile of the formula NC--R-R'CN from athiodinitrile of the formula NCR"SR"'CN wherein:

R, R, R" and R' are aliphatic or aromatic hydrocarbon radicals; and

R and R" have the same number of carbon atoms and R and R have the samenumber of carbon atoms comprising heating the thiodinitrile at atemperature of 200 to 700C.

2. The process of claim 1 wherein the temperature of reaction is300650C.

3. The process of claim 1 wherein the temperature is 400-600C.

4. The process of claim I conducted in the vapor phase.

5. The process of claim 1 wherein the reaction of the thiodinitrile isconducted in the presence of a solid.

6. The process of claim 5 wherein the solid contains a metal or mixturethereof.

7. The process of claim 6 wherein the metal or metals are selected fromthe Groups lllA, IVA, VA, VlA, IB, [IB, VB, VIB, VllB or VIII.

8. The process of claim 6 wherein the metal or metals are selected fromiron, nickel, manganese, copper, silver and tin.

9. The process of claim 6 wherein the metal is iron.

10. The process of claim 6 wherein the metal is copper.

11. The process of claim 1 wherein the reaction is conducted in thepresence of acrylonitrile, hydrogen or mixture thereof.

12. The process of claim 1 wherein thiodipropionitrile is reacted toproduce adiponitrile.

13. The process of claim 12 wherein the reaction is conducted in thepresence of acrylonitrile.

14. The process of claim 12 wherein the adiponitrile is recovered.

15. The process of claim 12 wherein the unreacted thiodipropionitrile isrecycled to the reaction.

1. A PROCESS FOR PRODUCING A DINITRILE OF THE FORMULA
 2. The process ofclaim 1 wherein the temperature of reaction is 300*-650*C.
 3. Theprocess of claim 1 wherein the temperature is 400*-600*C.
 4. The processof claim 1 conducted in the vapor phase.
 5. The process of claim 1wherein the reaction of the thiodinitrile is conducted in the presenceof a solid.
 6. The process of claim 5 wherein the solid contains a metalor mixture thereof.
 7. The process of claim 6 wherein the metal ormetals are selected from the Groups IIIA, IVA, VA, VIA, IB, IIB, VB,VIB, VIIB or VIII.
 8. The process of claim 6 wherein the metal or metalsare selected from iron, nickel, manganese, copper, silver and tin. 9.The process of claim 6 wherein the metal is iron.
 10. The process ofclaim 6 wherein the metal is copper.
 11. The process of claim 1 whereinthe reaction is conducted in the presence of acrylonitrile, hydrogen ormixture thereof.
 12. The process of claim 1 wherein thiodipropionitrileis reacted to produce adiponitrile.
 13. The process of claim 12 whereinthe reaction is conducted in the presence of acrylonitrile.
 14. Theprocess of claim 12 wherein the adiponitrile is recovered.
 15. Theprocess of claim 12 wherein the unreacted thiodipropionitrile isrecycled to the reaction.